Formed out of the gravitational collapse of opaque pre-stellar
cores, high-mass stellar objects, i.e.
with mass \(\ge 8\, \rm M_{\odot }\) , are cosmic regulators
of the cycle of matter at work in the interstellar medium (ISM)
of galaxies [1]}, [2]}.
One of their characteristic features is the fast and strong wind
blown out from their surface and powered by the complex nuclear
reactions at work in their interior.
Throughout their lives, massive stars first experience a rather
long, main-sequence phase corresponding to the burning of hydrogen in
their cores [3]}.
It is characterised by the release of diluted, hot and supersonic winds
from the stellar surface, and, once their hydrogen is exhausted, stellar
evolution is triggered.
The entire evolution of massive stars is fixed by their zero-age
main-sequence properties, such as their mass, angular velocity and chemical
composition, which uniquely determines their evolution and ultimate
fate [4]}, [5]}, [6]}, [7]}.
These initial stellar characteristics rule the time-dependence of
the stellar surface properties, as well as the number and duration of
the various evolutionary phases, up to their death, either as a core-collapse
supernova leaving behind a plerionic supernova
remnant, or directly collapsing as a black hole [8]}, [9]}, [4]}, [11]}, [12]}, [13]}, [14]}.
